1. Technical Field of the Invention
The present invention generally relates to the gaging of workpieces and more particularly to a gage designed to measure multiple diameters on a workpiece without the need for special part fixturing. As such, it is particularly useful as a post-process gage after a workpiece has been ground in an infeed centerless grinding process or other grinding process.
2. Related Technology
Numerous high precision components must be gauged to determine if their dimensional tolerances fall within an acceptable range prior to release to the end customer. An example of one such part is the hydraulic spool valves found in automotive transmissions. These spool valves are generally cylindrical in shape and include a series of raised and recessed lands formed thereon. The dimensions of these raised lands are critical since the valves slide within precisely dimensioned bores within the transmission assembly itself. If the lands are not properly dimensioned, performance of the transmission assembly may suffer or the transmission assembly may fail. Since a specific spool valve would be utilized in a large number of vehicles, should the manufacturing line machining these spool valves be in error, the end result is a large number of defective transmission assemblies.
In order to minimize the likelihood of a machining operation deteriorating to a point where the spool valves are out of compliance with the required dimensional tolerances, the current practice is to individually gage each and every spool valve. In gaging these parts, the spool valve is delivered to a gage assembly where the workpiece is fixtured and, then, an analysis of its dimensions is performed. After gauging, the spool valve is removed from the fixture and either passed through to an accepted parts bin or a rejected parts bin. If a series of parts deviating from the desired dimension are found to exist from a particular grinding station, then the grinding station can be identified for appropriate adjustment (automatic or manual) or for repairs.
Obviously, the individual fixturing and gaging of every workpiece is a time consuming and expensive proposition.
In view of the above there exists a need for a gage assembly where special fixturing of the workpiece is not required and wherein the cycle time in which to gage the workpiece is reduced.